CODEWITHSUNDEEP
x86device-driverosdevreal-mode
Justin Tokarchuk
Justin Tokarchuk

Reputation: 159

Limitations of real mode as it pertains to device driver development

My query is regarding device driver development.

If I wish to use real mode to make a Toy OS, but decide to write a network stack/set of network drivers, is there enough room to do so? Will I need to do like DOS and swap to Protected Mode to accomplish such a thing?

Upvotes: 1

Views: 235

Answers (1)

pitastic
pitastic

Reputation: 342

Implementing DNS, IP, TCP, UDP, ICMP, IGMP, ARP, MAC, etc. in real mode is possible, but some Network Card Drivers are quite big!

If you want to use BIOS interrupt routines I recommend switching to HUGE UNREAL MODE which allows you to access more memory, or use VIRTUAL 8086 MODE allowing you to create something like a 16-bit real mode virtual machine in 32-bit protected mode, so you can use all the benefits of PM and access BIOS Routines from it. That is assuming you don't mind switch to Protected Mode.

Upvotes: 1

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